A multi-channel communication system provides increased transmission capacity over other types of communication systems for various types of communication such as voice and data. Such a multi-channel system may be a multiple-input multiple-output (MIMO) communication system, an orthogonal frequency division modulation (OFDM) system, a MIMO system that utilizes OFDM, or some other type of system. A MIMO system incorporates multiple transmit antennas and multiple receive antennas to exploit spatial diversity. Spatial diversity may be used to support a number of spatial subchannels, each of which may be used to transmit data. An OFDM system effectively partitions the operating frequency band into a number of frequency subchannels (or frequency bins), each of which is associated with a respective subcarrier on which data may be modulated. A multi-channel communication system thus supports a number of “transmission” channels, each of which may correspond to a spatial subchannel in a MIMO system, a frequency subchannel in an OFDM system, or a spatial subchannel of a frequency subchannel in a MIMO system that utilizes OFDM.
The transmission channels of a multi-channel communication system typically experience different link conditions (e.g., due to different fading and multipath effects) and may achieve different signal-to-noise-plus-interference ratios (SNRs). Consequently, the transmission capacities (i.e., the information bit rates) that may be supported by the transmission channels for a particular level of performance may be different from channel to channel. As such, determining the power level allocation to each channel may be difficult. Adjusting power allocated to one channel may cause interference for another channel. Moreover, the link conditions typically vary over time. Therefore, in a time varying system, the determination of power allocation is increasingly difficult in a multi-channel communication system.
To this end as well as others, there is a need for techniques to effectively and efficiently determine power allocation to each channel in a multi-channel communication system.